The program [unreadable]Immune Function and Biodefense in Children, Elderly, and Immunocrompromised Populations[unreadable] will develop novel methods for protecting or treating immunocrompromised individuals at risk from bioterror threats. The research program covers the identification of biological mechanisms responsible for increased susceptibility to infection or decreased effectiveness of vaccines in these populations, as well as clinical research to test treatments designed to increase safety or efficacy. This research will lead to the prevention of infectious disease in children, the eldery and immunocompromised populations.